This article describes the Avastar User Interface in more detail. Due to the nature of the product the interface is rather large. Therefore we have split the interface into several functional groups. These groups are found at various places in the Blender  framework:

  • Export Panel is in Render properties
  • Shape controls Panel is in Object Properties
  • Rig Display Panel is in Object Data Properties
  • Expression Controllers are in Properties Sidebar
  • Mesh Tools are in Tool Shelf

The Avatar (3D View)

Adding an avatar to the current scene is easy. Just select “Avastar” from the Add menu. The avatar will be placed at the current cursor location on the current layer.


The entire Avastar object can be moved by selecting the rig (the orange circles) then move it just like every other Blender Object.

You can add as many Avastar characters to your scene as you like. This allows you to make multi character animations.

The Avatar Meshes

The avatar object is made up of eight meshes. The meshes are the standard SL meshes:

  • headMesh
  • upperBodymesh
  • lowerBodyMesh
  • eyeBallRightMesh, eyebalLeftMesh
  • skirtMesh
  • hairMesh
  • eyelashMesh

We have added materials to the main meshes:

  • avastar:mat:head
  • avastar:mat:upperBody
  • avastar:mat:lowerBody
  • avastar:mat:eyeBalls

Hint: All Avastar meshes provide SL compatible UV maps for textures. Therefore you can use Avastar also for creating texture based clothes. A detailed description is provided in the supplemental document “The OpenSim Avatar Mesh“.

Hint: The materials will only be created by Avastar when they do not yet exist in the current blend file.

One easy way to predefine your Avastar skin is by simply providing predefined materials in your blend file and use the listed material names. When you then add an Avastar character, it will be already textured.

The Avastar Bones

The bones are divided into 5 groups: “Control” (green), “IK” (yellow), “Volume” (bright red), “Attachment” (dark red), and “SL” (blue). Not all bones are visible by default. The display would otherwise become close to useless (see image to the right). We have chosen the default to display only those bones which are most relevant for animation.

A detailed description on what the Avastar rig is based can be found in the supplemental document “The OpenSim Skeleton“.

Animation Control Bones (green)

These are control bones for the usual SL bones (see below). These bones are used for posing and animating. They are very similar to the SL Bones but come with a small tweak: the Pelvis bone has been flipped around and made a child of the COG bone so that it’s easier to animate hip movement. Otherwise the sizes and parenting hierachy is the same as in SL. By default we have enabled “Custom Shapes”. that is the bones are not displayed as bones, but as control handles (green rings around the Avastar Mesh Character).

To see the bones in a more traditional form tick “X-Ray” and untick “Shapes” in the armature tab of the property editor. Note that there is a few more bones than you might expect as some of the bones are there to support the structure of the rig (some are hidden on a particular Armature layer – see the Armature tab of the Property Editor).

Note that we have split these bones into further subgroups that can be individually shown and hidden so you can enable only what you need:

  • Torso – the spine bones and COG (see below)
  • Arms – the arm bones
  • Legs – the leg bones
  • Origin – the origin marker for the avatar (see below)
  • Extra – some less used controlling bones (Foot, Toe, Skull, and Eye bones). Note that the eye bones are used indirectly for animation via the eye control bone.


IK Control Bones (yellow)

These bones belong to the IK (Inverse Kinematics) system. By default these bones are invisible and the influence of these bones is set to zero. To enable IK control select a bone on a limb and use the sliders in the “Rig Properties” section of the Properties Panel.

When switched on the whole limb will try and align with the position of the IK control. Note that there are a bunch of bones that are there to provide a target for the IK system and to show you how a limb is orientated. The latter bones can be made visible with the “IK Rig” visibility switch below.


SL Bones (blue)

These are the “true” bones of the SL Character. These bones are used to do the weighting for your own mesh characters or mesh attachments. When it comes to export of your mesh, then (by default) this is the only set of bones which are taken into account. But see for more details in the export options.

For animations these are the only bones that count (together with the Origin which provides the reference point for the entire entire avatar).



Root Bones (green)

We provide 2 extra bones for making animation easier:

The Origin for moving the entire rig regardless of animation and the COG Bone for animating entire character movements:

  • The Origin: This bone is at the feet and is shaped like a four pointed arrow. All the animations are relative to this bone so moving it around won’t change the animation, it just gives you another handle to position the avatar and it represents the floor for the avatar. If you were creating a multiple-avatar animation, think of puting the Origin bones where you would place the pose-balls.
  • The COG Bone (Center Of Gravity Bone): The COG is how you rotate or move the character as a whole. The Pelvis and Torso are children of this bone and everything else is a child of those. Normally this bone is a small green circle near the small of the back. In contrast to the movement of the Origin, any moves or rotations of the COG bone will be recorded in your animation.

Attachment Points (Red spheres)

The attachment points correspond to the attachment points of the Avatar. These points are primary used for animation. But we also support weighting of the attachment points. Unfortunately, SL doesn’t appear to support repositioning these bones.

Note: Most suported online worlds do not officially support weighting of attachment points. And not all attachment points can (currently) be used for weighting. In particular all attachment points which contain a space in their name (e.g. “L UpperArm”) will not be recognized as”weighted bone” during import to OpenSim or a compatible online world.


Collision Volumes (red)

The Collision Volumes correspond to the collision volumes in the Avatar. Originally these bones provide a simple mesh frame that allows efficient (fast) calculations of physical interaction (collisions) of your avatar with the environment. However these bones can also be used for animation and weighting. The most important feature of the Collision Volumes is that they are coupled to the SL Shape sliders. And if correctly weighted, they allow your meshes to be customizable via the SL Slider system.

Note: This feature is also fully independent(!) from the Mesh deformer project which is currently implemented by Karl Stiefvater in the “Mesh clothing parametric deformer” project.


Note: This feature works on all online world viewers which support Mesh. Detailed information about weighting to the Collision volumes will be provided.

Rotation Limits

[PS Showtime url=”/wp-content/uploads/2012/08/map_rig_properties.png”]

Some of the (green) Rig Control Bones have been constrained with rotation limits. These limits ensure that your poses keep reasonable (avoid impossible poses). But sometimes -especially for non human rigging- you want to disable these limits.

The rotation Controls are part of the Rig Controls Panel. The buttons Disable and Enable apply to the set of selected bones by default.


Note: When you have ticked All Bones, then the enable/disable buttons affect all bones.

Inherit Rotation

Child rotations normally inherit the rotation of their parent bones. This inheritance can be easily enabled or disabled for following bones:

  • Head inherits from Neck
  • Neck inherits from Chest
  • Chest inherits from Torso
  • Shoulders inherit from Collar

An Example

A small example may help to understand what happens: The Head can be decoupled from neck rotations. In the default case the rotation is inherited.When you now rotate the Chest, this rotation will be forwarded to the children of the Chest, here to the Neck and collars. Subsequently the inheritance will pass down to the leaf bones, thus the entire upper body follows the rotation.


When you move you naturally you tend to keep your head vertical. Decoupling the Head from the Neck rotation helps to achieve a similar behavior of the Avastar character. In the image you see what happens

When the rotation inheritance is disabled, the Head keeps in the upward position regardless of the rotation of the Chest. In the same way, keeping the orientation of the chest regardless of the lower body can be useful in some motions.

Note: The inherit rotation buttons can be key framed into the animation.


The Breath controler allows to add a subtle breath movement which affects the spinal column from the Pelvis up to the Head. The bone that gets the most influence is the Torso, which gets rotated along the x axis.

You can press Breath In/Breath Out multiple times to get a “deeper breath”.

The following pictures demonstrate how the Torso and the Chest move against each other to simulate the breathing:


After a few Breath In Clicks


After a few Breath Out Clicks


Animation Export

[PS Showtime url=”/wp-content/uploads/2012/08/map_render.png”]
The Avastar Animation exporter exports Skeletal animations of the Avastar Armature. We support 2 export Modes (anim and BVH).

Note: The Exporter is only available when you have selected the Avastar Armature as the active Object.
The Animation Export Panel is located in the Render Properties Section (see navigation map by hovering the mouse over the zoomglass above). You have to scroll down to the bottom of the section.

Anim Export

Basic Settings

The Anim export creates data files in the same animation format that is also used by SL, OpenSim etc. One advantage of this export type is that it supports the animation of the Eye Bones.

  • fps: (Frames Per Sec).
  • Start Frame: First frame to export.
  • End Frame: Last frame to be export.
  • Ease in: Time in seconds until the character will be reposed from the character’s current pose to the first pose in the Start Frame.
  • Ease Out: Time in secs until the character will be reposed from the End Frame to the character’s previous pose.
  • Priority: [-1, 0 … 6] Animation priorities (1)

(1): Priorities from 0 to 5 correspond to SL’s priority system. Priority 6 is like a master priority that “rules them all”. But it is not officially supported. Priority -1 probably means “ignore this joint”, but i could not find a description of what it does.

Loop Settings

  • Loop Animation (checkmark): if checked, the animation will run in an infinite loop. If unchecked, the animation will run exactly once.
  • In: First frame of loop (can be anywhere in the animation)
  • Out: Last frame of loop (needs to be right from the In location) Note: Last Frame and First frame can be the same for a static animation!
  • name:name of the animation. This is actually a name template. It can contain variables:
    • $action: Name of current action
    • $avatar: name of the Armature

Export Settings

  • Apply Armature Scale: This is an advanced feature. Export non-Pelvis bone locations to the animation where they are keyframed. Note that if you move the bones (not just rotate them) then it’s easy to break your avatar in such a way that it will require logging out from SL and Relogin to fix.
  • Use Transalations:
  • Export Animation: Clicking this button will open a file selection box and after you have specified the name of the export file (pre-filled out with the template), the data is exported to disk.

BVH Export:

The BVH export is compliant to standard BVH, but it takes care about some conventions which are needed by the SL animation Importer. What these conventions are needs to be documented still.


  • fps: (Frames Per Sec)
  • Start Frame: The first frame to be exported
  • End Frame: the last frame to be exported
  • name:name of the animation. This is actually a name template. It can contain variables:
    • $action: Name of current action
    • $avatar: name of the Armature
  • Prepend reference: Automatically add the Reference Frame as initial frame (the reference frame is needed by the animation system of OpenSim and compatible worlds)
  • Export Animation: Clicking this button will open a file selection box and after you have specified the name of the export file, the data is exported to disk.

Note: During upload to your online world you can specify animation loops. The in and Out locations need to be specified in %. We have added a loop % calculator. Just enter the in frame and the Out frame. Avastar will calculate the percentage values as you need them for the animation importer.

The Avastar Shape (Properties, Object Section)

Avastar can import and export shapes from OpenSim or any compatible online world. You find the import/export functions in the Object properties of the Avastar Armature:

  • Go to object mode.
  • Select the Rig (RMB on the yellow circles around the mesh).
  • Open the Properties window.
  • Navigate to the “Object” properties.

There you find a panel Avatar Shape IO. This panel displays a Preset selector and a subpanel with 4 main functions.

[PS Showtime url=”/wp-content/uploads/2012/11/map_appearance_io.png”] appearance_io_01

Load Shape

This function allows you to upload a Shape that you have previously exported from your online world: In most viewers there is a shape export option hidden in the advanced menu (“Advanced” -> “Character” -> “Charater Tests” -> “Appearance to XML”). This will silently create a file called:

[application_folder]/character/new archetype.xml

This file contains your current shape and can be loaded into Avastar, where [application_folder] is the viewer’s application data folder. For Windows this folder is located  at:


Save Shape to

By default this function creates a new Shape file with your current shape settings. This file can later be used for Load Shape (see above). Right besides the function you find a selector for the save destination.

As mentioned above the default option is to save to File. But you can also save to a Blender textblock. In that case the slider values can be found in the Blender text editor panel. The values correspond to the shape settings in the SL viewer.
[PS Showtime url=”/wp-content/uploads/2012/11/map_appearance_io.png”]

Note: Some viewers support the upload of shape file to SL (e.g. Firestorm, Singularity). To see the file, switch to the Blender Text editor and locate Shape for: Avatar  (Avatar stands for the name of the Armature). Useful when you need to update the shape in SL with the values from blender.

Refresh Shape:

This resets the Avastar meshes to the current Shape values. Useful together with the new custom shape key function (see below). Also if you messed up the Avastar meshes (by editing them) you can return the mesh back to the current shape slider values.

Warning: if you added or removed vertices from the Avastar meshes, this function will fail!

Delete Avastar Shapes

Remove all Shapes from the Avastar character. You will want this when you use the rig for non human characters where keeping the Avastar human meshes make no sense.

Load Shape Editor

When you load a blend file which contains an Avastar Character, then the Shape panel sometimes only displays the “Load Shape Editor” Button. This happens when you just have started Blender).
Activating the button loads the shape setting controls. We added this for optimization purposes as it takes a few seconds to initialize the Avastar shape system.

The Shape Sliders

[PS Showtime url=”/wp-content/uploads/2015/06/map_appearance_sliders.png”]

We support the same shape slider system as you can find in SL, OpenSim or other compatible worlds. You find the sliders in the Object properties of the Avastar Character:

  • Go to object mode.
  • Select the Rig (RMB on the yellow circles around the mesh).
  • Open the Properties window and navigate to the “Object” properties.
  • There you find a panel “Avatar Shape”.

Avastar-1.6: Avatar Appearance Panel has been redesigned and is also available in the Toolshelf.

  • Height: The current height of the character in online world units (1.87 meters in this example, note that Avatars tend to be slightly bigger than real world people).
  • Section: A popup Menu for the different Shape Sections. This is equal to the Shape Editor in SL or OpenSim.
  • Male: A Gender selector. By default the gender is female. If you check the selector, the Avastar character changes to male. You can switch the gender at any time.

up to Avastar-1.5: Avatar Shape Panel

The Section Sliders

The section subpanel of the Avatar shapes panel contains the Sliders for the section specific shape keys. The values assigned in SL match exactly with the slider values in Blender.

  • Some sliders have a small stickman icon on their left side. This indicates the slider affects the bones (bone sliders).
  • Since Avastar-1.5: Some sliders have a small magnet icon on their left side. This indicates the sliders affects a fitted Mesh bone (Collision Volume bone)
  • All other sliders affect only the mesh (morph sliders).
  • The icons on the right side indicate that the slider value has been changed. Click on these icons to reset the corresponding Slider Value to its default.
  • Note: The Reset icon on the Top Left resets the entire Bone Section to its Default Values.

Before Avastar-1.5: click on the Reset default icons to get back the slider’s default value.

Avastar-1.5: Fitted Mesh Sliders indicated with a magnet

The Special Sections

[PS Showtime url=”/wp-content/uploads/2012/11/map_appearance_sections.png”]
  • We have added 2 extra sections Changed, and Skeleton which do not appear in the Second Life Shape editor.  The Changed section is empty by default and will be populated by the list of changed Shape sliders of your Avastar. The Skeleton section (see image) contains all sliders which will change the bone length of the Avastar character.
  • On top of the list (in the Section Header) you see a Reset button. This button will reset all shape sliders of the current Section to its factory defaults.
  • Each slider can be dragged, or you can click on it and then type in a number.
  • If a slider has been changed then you will see a reset icon right to the slider. Clicking on that icon will reset the slider to its default value.

Avastar-1.6 Slider Section (slightly modified compared to previous Versions)

Hint: If you plan to create Meshes compatible to the Mesh Deformer, then you will want to reset all bones in the Skeleton Section to their default values (Reset Section to defaults).
Note: The Mesh Deformer project has been abandonned in Second Life. However it is used in OpenSim and some other virtual worlds. Therefore we have not removed the support for the Mesh Deformer.

Face Expressions

[PS Showtime url=”/wp-content/uploads/2012/11/map_expressions.png”]

Avastar supports hand expressions and face expressions.

  • Hand Expressions: We support all 15 SL Hand expressions.

    Note: An SL Animation can only contain one single Hand expression. And this hand expression will remain valid for the entire animation sequence. If you need to change the Hand expression you will have to split the animation into pieces and then merge the animations in the SL animation editor.
  • Face expressions: Unlike hand expressions face expressions are implemented as Shape keys. We support all 20 face expressions. In Blender the face expressions can even be animated (key framed). However this fine detail of animation is not (yet?) available in OpenSim or other compatible online worlds. But for Blender animations the expressions are fully implemented and can be combined and key framed.


Rig Display Properties

[PS Showtime url=”/wp-content/uploads/2012/08/map_rig_display.png”]

The Rig Display section gives you full control over which parts of the Mesh and the Rig can be seen at a given time. By default only the Control bones and the main parts of the Avastar mesh are visible. But sometimes it is desirable to hide or unhide parts of the Rig or parts of the Avastar meshes.

Furthermore the control bones (green) use custom shapes by default. That is, they are formed as rings which are placed around the Avastar body. The benefit of the custom shapes is that they can be selected easier. But sometimes it is desired to switch from Custom shapes back to Blender’s default shapes (Sticks or Octahedrons).

The Rig Display panel is subdivided into three major parts:

Control Style settings

The first 2 buttons in the Rig display settings panel are used for switching between custom shape and blender’s default shape:

  • Custom Shapes: Set all control bones to use custom shapes (Default)
  • Stick Shapes: Set all bones to use Blender’ default shapes.

You can switch between both display options at any time. But when you switch to Custom Shapes, then the bone X-Ray setting is automatically disabled, while when you switch to Stick Shapes, the X-Ray setting is automatically enabled.

Armature tools

The Armature tools are located in the Tool Shelf (left navigation bar in the 3D View) There you find a panel named “Custom mesh” and in that panel you see “SL Bone Control” and “Show Bones”.The sub panels only appear when the Armature is selected!

SL Bone Control

There are situations where it is desirable to move/rotate the SL bones. For example during weightpainting you may want to pose the SL bones while painting on the mesh. But the SL bones can by default only be moved/rotated indirectly by posing the control bones. This is where the Armature Editing functions step in.

  • SL Bone rotations:
    Unlock to allow rotation of the SL bones during posing.
    Lock after you are done with weight painting.
    Note: When some bone rotations are locked, other bones are unlocked, then you will see 2 buttons (for “Lock” and “Unlock”) side by side.
    Note: Locking snaps the SL bones back to the Control bones. This is intended behaviour!
  • SL Bone location:
    Unlock to allow location changes of the SL bones during posing.
    Lock after you are done with weight painting.
    Note: When some bone locations are locked, other bones are unlocked, then you will see 2 buttons (for “Lock” and “Unlock”) side by side.
    Note: Locking snaps the SL bones back to the Control bones. This is intended behaviour!
  • Structure Select:
    The Avastar Bone set also contains a few structure bones. These bone are normally not selectable.
    enable: make the structure bones selectable (for move and rotation)
    disable: make the structure bones unselectable (default)
    Note: When some structure bones are enabled for select, and others not enabled for select, then you will see 2 buttons (for “enable” and “disable”) side by side.

  • Bake Rest Pose:
    Use this function if you want to make the current bone setup a new rest Pose. This is mostly useful when you are creating non human rigs.
  • Snap SL Bones to Rig:
    Most useful function to automatically move SL Bones to the same location/rotation as the related Avastar control bones. You use this function after you edited the skeleton to match your very special (non human) mesh character.
  • Snap IK Bones to Rig:
    Same as for SL Bones, but for IK Bones.

Show Bones

The Show Bones panel is a convenience tool. Actually it provides functions which normally are only available when the Armature is selected. But especially when you are in weight paint mode, you might want to change the visibility and shape of the bones.

  • Armature Display
    The buttons allow to switch the skeleton shape.
  • Presets
    • Preset: Weight
      Preset for weight painting.
    • Preset: Animation
      Preset for animation.
  • Bone Groups visibility
    These buttons control which of Avastar’s bone groups are shown or hidden.